<template>
<div>
   <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <div class="iconfont header-abs-back">&#xe624;</div>
   </router-link>
   <div
       class="header-fixed"
       v-show="!showAbs"
       :style="opacityStyle">
      <router-link to="/">
          <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
      景点详情
   </div>
</div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
     return {
        showAbs: true,
        opacityStyle: {
           opacity: 0
        }
     }
  },
  methods: {
    handleScrollhandleScroll () {
        const top = document.documentElement.scrollTop
        if (top > 60) {
           let opacity = top / 140
           opacity = opacity > 1 ? 1 : opacity
           this.opacityStyle = { opacity }
           this.showAbs = false
        } else {
            this.showAbs = true
        }
    }
  },
  activated () {   // 页面每一次展示都会执行
     window.addEventListener('scroll',this.handleScroll)
  },
  deactivated () {  //页面即将被替换成心的页面的时候会执行
    window.removeEventListener("scroll",this.handleScroll)
  }

}
</script>

<style lang="stylus" scoped>
   @import '~styles/varibles.styl'
   .header-abs
       position: absolute
       left: .2rem
       top: .2rem
       width: .8rem
       height: .8rem
       line-height: .8rem
       border-radius: .4rem
       text-align: center
       background: rgba(0,0,0,.8)
       .header-abs-back
          color: #fff
          font-size: .4rem
   .header-fixed
       z-index: 2
       position: fixed
       top: 0
       left: 0
       right: 0
       height: $headerHeight
       line-height: $headerHeight
       text-align: center
       color: #fff
       background: $bgColor
       font-size: .32rem
       .header-fixed-back
          position: absolute
          top: 0
          left: 0
          width: .64rem
          text-align: center
          font-size: .4rem
          color: #fff
</style>
